1. Field of the Invention
The present invention relates to a subcool and/or precool system for the liquid refrigerant and/or hot gas discharge refrigerant of an air conditioning, refrigeration or heat pump system (cooling mode) that utilizes either the exhaust air required for clean air operation of a building's conditioned air supply only, or the exhaust air and the condensate discharge from said air conditioning, refrigeration or heat pump system (or other water source), or outside air and said condensate (or other water source) to accomplish said subcooling and/or precooling for purposes of increasing the capacity and efficiency of said air conditioning, refrigeration or heat pump system.
The present invention further relates to a system for ducting the building exhaust air or outdoor air to said subcool and/or precool system. Said building exhaust air to be used after a preliminary sensible heat exchange with the required incoming make up air if possible.
The present invention also relates to a system for piping the condensate of said air conditioner and/or heat pump system (or other water source) to the subcooling and/or precooling heat exchangers.
Also, the present invention additionally relates to a water sump and pump system or capillary feed system for continually wetting the subcool and/or precool heat exchangers with the condensate (or other water source) while the exhaust air or outside air is blowing across the wetted subcool and/or precool heat exchangers for purposes of evaporatively subcooling and/or precooling the refrigerant.
This invention more particularly pertains to an apparatus and method comprising a building exhaust air or outdoor air supply and air conditioner condensate (or other water source) evaporative subcooler where said subcooler is serially located between the air conditioning, refrigeration or heat pump systems' condenser and its evaporator. This invention also more particularly pertains to an apparatus and method comprising a building exhaust air and air conditioning condensate (or other water source) evaporative precooler where said precooler is positioned serially between the air conditioning, refrigeration or heat pump system compressor and its condenser.
Next, this invention also more particularly pertains to an apparatus and method whereby said building exhaust air or outdoor air and air conditioner condensate (or other water source) may be first used to evaporatively subcool the liquid refrigerant and then the exhaust air and water are subsequently used to evaporatively precool the hot gas discharge refrigerant.
Further, this invention also more particularly pertains to an apparatus and method whereby said building exhaust air or outdoor air and air conditioner, refrigeration or heat pump condensate (or other water) may be first used to evaporatively subcool the liquid refrigerant and then the exhaust air discharge from the subcooler only, being used to conductively precool the hot gas discharge refrigerant.
Additionally, this invention more particularly pertains to an apparatus and method comprising a duct system that directly feeds the building exhaust air or outdoor air through said wetted subcooler and/or precooler or that feeds said building exhaust air, after sensible heat exchange with incoming make up air, to said wetted subcooler and/or precooler.
This invention also more particularly pertains to an apparatus and method for directing the condensate of an air conditioning, refrigeration or heat pump system to said subcooler and/or precooler. If condensate is not adequate or not available, another water source with a float control to keep the water level where needed can be directed to said subcooler and/or precooler.
This invention also more particularly pertains to an apparatus and method comprising either a pump and distribution system for keeping the subcooler and/or precooler heat exchanger surfaces wetted or a capillary system for accomplishing same.
Where the primary system is a heat pump, operating in the heating mode, another function of the present invention would be to utilize the building exhaust air or outdoor air only to first subcool the liquid refrigerant and then reuse the air supply after absorbing the heat from the subcooler to add heat to the postheater(precooler in the cooling mode). This is made possible by locating the precooler/postheater heat exchanger in the heat pump circuit serially between the reversing valve and the outdoor coil.
Additionally, this invention also relates to an apparatus and method where relatively cool building exhaust air only is used only to subcool the liquid refrigerant.
Next, this invention also relates to an apparatus and method where relatively cool building exhaust air only is used only to desuperheat the hot gas refrigerant.
Also, this invention relates to an apparatus and method where relatively cool building exhaust air only is first used to subcool the liquid refrigerant and then is reused to desuperheat the hot gas refrigerant.
Finally, this invention relates to an apparatus and method where relatively warm building exhaust air only is first used to postheat the evaporating refrigerant after the primary outdoor evaporator of a heat pump, operating in the heating mode.
2. Description of the Background Art
Presently there exist many types of devices designed to operate in the thermal transfer cycle. The vapor-compression refrigeration cycle is the pattern cycle for the great majority of commercially available refrigeration systems. This thermal transfer cycle is customarily accomplished by a compressor, condenser, throttling device and evaporator connected in serial fluid communication with one another. The system is charged with refrigerant, which circulates through each of the components. More particularly, the refrigerant of the system circulates through each of the components to remove heat from the evaporator and transfer heat to the condenser. The compressor compresses the refrigerant from a low-pressure superheated vapor state to a high-pressure superheated vapor state thereby increasing the temperature, enthalpy and pressure of the refrigerant. A superheated vapor is a vapor that has been heated above its boiling point temperature. It leaves the compressor and enters the condenser as a vapor at some elevated pressure where the refrigerant is condensed as a result of the heat transfer to cooling water and/or to ambient air. The refrigerant then flows through the condenser condensing the refrigerant at a substantially constant pressure to a saturated-liquid state. The refrigerant then leaves the condenser as a high pressure liquid. The pressure of the liquid is decreased as it flows through the expansion valve causing the refrigerant to change to a mixed liquid-vapor state. The remaining liquid, now at low pressure, is vaporized in the evaporator as a result of heat transfer from the refrigerated space. This vapor then enters the compressor to complete the cycle. The ideal cycle and hardware schematic for vapor compression refrigeration is shown in FIG. 1 as cycle 1-2-3-4-1. More particularly, the process representation in FIG. 1 is represented by a pressure-enthalpy diagram, which illustrates the particular thermodynamic characteristics of a typical refrigerant. The P-h plane is particularly useful in showing the amounts of energy transfer as heat. Referring to FIG. 1, saturated vapor at low pressure enters the compressor and undergoes a reversible adiabatic compression, 1-2. Adiabatic refers to any change in which there is no gain or loss of heat. Heat is then rejected at constant pressure in process 2-3. An adiabatic pressure change occurs through the expansion device in process 3-4, and the working fluid is then evaporated at constant pressure, process 4-1, to complete the cycle. However, the actual refrigeration cycle may deviate from the ideal cycle primarily because of pressure drops associated with fluid flow and heat transfer to or from the surroundings. It is readily apparent that the temperature of the liquid refrigerant plays an important role in the potential for removing heat in the evaporator phase of the thermal cycle. The colder the liquid refrigerant entering the evaporator, the greater the possible change in enthalpy or heat energy absorbed per unit mass of liquid available for vaporization and the colder the liquid refrigerant entering the expansion device leading to the evaporator, the lower the flash gas loss, which means a higher portion or percentage of mass is available for vaporization through the evaporator.
Also, it is readily apparent that rapid precooling of the hot gas discharge from a compressor lowers compressor power consumption, improves compressor efficiency and improves the primary condenser's performance. It is also readily apparent that adding more heat to the evaporator (postheater) of a heat pump in the heating mode improves the systems' coefficient of performance. Many such devices and methods currently exist that are designed to accomplish this subcooling and precooling or postheating.
However, these known methods and devices have drawbacks. The drawbacks include the high cost of accomplishing the subcooling and/or precooling and/or postheating, and/or the ineffectiveness or degrading effectiveness of the subcooling and/or precooling and/or posting method and/or device.
In response to the realized inadequacies of earlier methods and devices, and because of the recently mandated indoor clean air act that requires a certain percentage of indoor air to continually be replaced, it became clear that there was a need for a liquid refrigerant subcooler for an air conditioning or heat pump system that has a low initial cost as well as having a method for utilizing the relatively cold, dry air that is exhausted from a building air supply for purposes of maintaining good indoor air quality as well as for alternatively also utilizing the condensate from said air conditioning or heat pump (or other water source) to accomplish said subcooling conductively or evaporatively, or to use the condensate and alternatively the outdoor air to subcool evaporatively.
It is also readily apparent that rapid precooling of the hot gas discharge from a compressor reduces head pressure, decreases power consumption, increases refrigerant mass flow and improves the efficiency of an air conditioner, refrigeration or heat pump system.
The use of the relatively cold, dry exhaust air only, or with the use of the exhaust air or alternatively with the use of outdoor air and the use of the condensate (or other water source) directly or even after the exhaust air only or exhaust air and condensate being first used to subcool the liquid refrigerant or alternatively after outdoor air and condensate being first used to subcool the liquid refrigerant, will provide this precooling in a very cost effective manner.
The building exhaust air is warm relative to outside air when heating is required by a heat pump, therefore another objective of the present invention is to reclaim the heat in the exhaust air by using this exhaust air to first reclaim heat from the subcooler then subsequently provide additional heat to a secondary evaporator, a postheater (precooler in the cooling mode), or alternatively to use the exhaust air without first subcooling to postheat the refrigerant when a heat pump is operating in the heating mode.
Therefore, the principal objective of this invention is to provide an improvement which overcomes the aforementioned inadequacies of the prior art devices and provides improvements which are a significant contribution to the advancement of the subcooler and/or precooler and/or postheater art for air conditioner, refrigeration or heat pump systems.
Another objective of the present invention is to provide a more constant subcooling over a wide range of air source or water source condenser conditions.
Still another objective of the present invention is to provide a conductive or evaporative cooling to the liquid refrigerant of an air conditioning, refrigeration or heat pump system.
Yet another objective of the present invention is to provide increased cooling capacity by means of the subcooling of the liquid refrigerant.
Still yet another objective of the present invention is to provide rapid precooling of the hot gas refrigerant discharge from a compressor by utilizing the relatively cold, dry building exhaust air only or exhaust air and condensate or alternatively outdoor air and condensate (or other water source) directly to provide a conductive or an evaporative cooling process that will provide for precooling of the hot gas refrigerant or even after both exhaust air only or exhaust air and water or alternatively outdoor air and water being first used to conductively or evaporatively subcool the liquid refrigerant.
Yet a further objective of the present invention is to provide an alternate means for precooling the hot gas refrigerant after first conductively or evaporatively subcooling the liquid refrigerant with the building exhaust air only or with the exhaust air and water or alternatively with outdoor air and water, whereby the exhaust air exiting the subcooler is used only, to conductively cool the precool heat exchanger, which in turn precools the hot gas refrigerant passing through the precooler.
Still another objective of the present invention is to provide higher efficiency in the heating mode of a heat pump by utilizing the relatively warm building exhaust air to provide additional heat to the evaporating refrigerant in a secondary evaporator, a postheater, located serially between the primary evaporator and the reversing valve that functions as a precooler in the cooling mode of the heat pump.
Yet still another objective of the present invention is to first use the building exhaust air to subcool the liquid refrigerant in a subcooler, which adds more heat to the exhaust air, before subsequently passing the subcooler heated building exhaust air through the postheater and adding even more heat to the evaporating refrigerant.
And yet another objective of the present invention is to provide lower power consumption and increased pumping efficiency of the compressor, as well as to improve the primary condenser's performance.
Even yet another objective of the present invention is to provide a means for ducting and supplying the building exhaust air or alternatively outdoor air to the subcool and/or precool and/or postheat heat exchangers.
Yet a further objective of the present invention is to provide a means for capturing and directing the condensate of an air conditioning, refrigeration or heat pump system to the subcool and/or precool heat exchangers.
And yet another objective of the present invention is to provide a means for providing water directly to said subcool and/or precool heat exchangers if condensate is not available or is not adequate.
Yet a further objective of the present invention is to provide a means for mechanical pumping or passive capillary pumping of said condensate or other water to said subcooler and/or precooler heat exchangers to keep said subcooler and/or precooler heat exchangers wetted.
The foregoing has outlined some of the pertinent objects of the invention. These objects should be construed to be merely illustrations of some of the more prominent features and applications of the intended invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure.
Accordingly, other objects and a more comprehensive understanding of the invention may be obtained by referring to the summary of the invention, and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.